Question

A beam of light containing red (660 nm) and violet (410 nm) wavelengths travels from air, through a flat piece of crown glass 2.24 cm thick, and then back to air.

(a) If the beam has an angle of incidence of 38.6° in air, determine the angle at which the two colors of light emerge from the crown glass. The index of refraction respectively for red and violet light in crown glass is 1.512 and 1.530. (Enter a number to three decimal places.)

red _____	°
violet _____	°

(b) Determine the distance separating the red and violet light as it emerges from the glass.
______ cm

Answer 1

Part A)

From Snell's Law, the angle it enters will be the angle it exits. Both will still be 38.6°

Part B)

But inside the glass, they will have different angles

n₁(sin i) = n₂(sin r)

1(sin 38.6°) = 1.512(sin r)

r = 24.37° for the red

The distance horizontally it travels is from the tangent function

tan(24.37°) = x/2.24

x = 1.01 cm

Next

1(sin 38.6) = 1.530(sin r)

r = 24.06° for the violet

The distance horizontally it travels is from the tangent function

tan(24.06) = x/2.24

x = 1 cm

Subtract the two for the difference

(1.01) - (1 ) = 0.01 cm